Divide ad spend by ad-attributed sales to get advertising cost of sales, the inverse of ROAS.
The advertising cost of sales is the share of sales attributed to ads that ad spend represents, expressed as a percentage. The same figure is also shown per 1,000 and as a "one in every N" odds statement, which is easier to reason about when the rate is very small. Absolute counts hide scale — a rate normalises the number so you can compare periods, channels or cohorts of different sizes, where lower is better.
ACOS
ACOS = Ad spend ÷ Sales attributed to ads × 100
ACOS = Ad spend ÷ Sales attributed to ads × 100 The advertising cost of sales is the share of sales attributed to ads that ad spend represents, expressed as a percentage. The same figure is also shown per 1,000 and as a "one in every N" odds statement, which is easier to reason about when the rate is very small.
Absolute counts hide scale — a rate normalises the number so you can compare periods, channels or cohorts of different sizes, where lower is better.
This calculator takes 2 inputs: Ad spend, Sales attributed to ads. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.